Organotin thiocarboxylates and preparation thereof

ABSTRACT

A PROCESS IS PROVIDED FOR PREPARING DIORGANOTIN MONOTHIOCARBOXYLATES AND SUCH DIORGANOTIN MONOTHIOCARBOXYLATES CONTAINING ADDITIONAL GROUPS, INCLUDING DIORGANOTIN MONOHALIDE MONOTHIOCARBOXYLATES, BY REACTING A DIORGANOTIN SULFIDE WITH AN ACYL HALIDE TO FORM A DIORGANOTIN MONOHALIDE MONOTHIOCARBOXYLATE, AND OPTIONALLY FURTHER REACTING THE DIORGANOTIN MONOHALIDE MONOTHIOCARBOXYLATE WITH AN ACTIVE HYDROGEN COMPOUND SUCH AS (A) A STRONG INORGANIC ACID TO LIBERATE THE CORRESPONDING FREE THIOL ACID; OR (B) WITH A WEAK ORGANIC ACID, SUCH AS A MERCAPTAN, MERCAPTOESTER, THIOL ACID, OR CARBOXYLIC ACID, OR CARBOXYLIC ACID ESTER OR (C) AN ALCOHOL TO FORM A DIORGANOTIN MONOMERCAPTIDE MONOTHIOCARBOXYLATE, A DIORGANOTIN MONOMERCAPTO ACID ESTER MONOTHIOCARBOXYLATE, A DIORGANOTIN DITHIOCARBOXYLATE, A DIORGANOTIN MONOCARBOXYLATE MONOTHIOCARBOXYLATE, OR A DIORGANOTIN MONOALCHOLATE MONOTHIOCARBOXYLATE. DIORGANOTIN MONOHALIDE MONOTHIOCARBOXYLATES AND DIORGANOTIN MONOMERCAPTO ACID ESTER MONOTHIOCARBOXYLATES ARE ALSO PROVIDED.

United States Patent 3,775,451 ORGANOTM TIHOCARBOXYLATES AND PREPARATION THEREOF Lawrence Brecker, Brooklyn, N.Y., assignor to Argus Chemical Corporation, Brooklyn, N.Y.

No Drawing. Original application May 20, 1969, Ser. No. 826,299, now Patent No. 3,630,992. Divided and this application Feb. 11, 1971, Ser. No.'114,715

Int. Cl. C07f 7/22 US. Cl. 260-4297 18 Claims ABSTRACT OF THE DISCLOSURE A process is provided for preparing diorganotin monothiocarboxylates and such diorganotin monothiocarboxylates containing additional groups, including diorganotin monohalide monothiocarboxylates, by reacting a diorganotin sulfide with an acyl halide to form a diorganotin monohalide monothiocarboxylate, and optionally further reacting the diorganotin monohalide monothiocarboxylate with an active hydrogen compound such as (a) a strong inorganic acid to liberate the corresponding free thiol acid; or (b) with a Weak organic acid, such as a mercaptan, mercaptoester, thiol acid, or carboxylic acid, or carboxylic acid ester or (c) an alcohol to form a diorganotin monomercaptide monothiocarboxylate, a diorganotin monomercapto acid ester monothiocarboxylate, a diorganotin dithiocarboxylate, a diorganotin monocarboxylate monothioearboxylate, or a diorganotin monoalcoholate monothiocarboxylate.

Dirganotin monohalide monothiocarboxylates and diorganotin monomercapto acid ester monothiocarboxylates are also provided.

This application is a division of US. application Ser. No. 826,299, filed May 20, 1969, now US. Pat No. 3,630,992, patented Dec. 28, 1971.

This invention relates to a process for preparing diorganotin monothiocarboxylates and such diorganotin monothiocarboxylates containing additional groups, by reacting a diorganotin sulfide with an acyl halide to form a diorganotin monohalide monothiocarboxylate and, optionally, further reacting the diorganotin monohalide monothiocarboxylate with an active hydrogen compound, such as (a) a strong acid to form the corresponding free thiol acid; or (b) a Weak organic acid, such as a mercaptan to form a diorganotin monomercaptide monothiocarboxylate; or a mercapto acid ester to form a diorganotin monomercapto acid ester monothiocarboxylate; or a thiol acid to form a diorganotin dithiocarboxylate; or a carboxylic acid to form a diorganotin monocarboxylate monothiocarboxylate; or (c) an alcohol to form a diorganotin monoalcoholate monthiocarboxylate; to diorganotin monohalide monothiocarboxylates and diorganotin monomercapto acid ester monothiocarboxylates, which can be prepared in accordance with the above process; and to polyvinyl chloride compositions containing diorganotin monohalide monothiocarboxylates and/or diorganotin monomercapto acid ester monothiocarboxylates.

PRIOR ART I Diorganotin dimercaptides have been used as stabilizers for polyvinyl chloride resins were sulfur-containing organotin stabilizers are desired. Diorganotin dithiocarboxylates have also been known as stabilizers for polyvinyl chloride for some time. Both these types of organotin compounds display similar stabilizing effectiveness typical of d-iorganotin mercaptides; the diorganotin dithiocarboxylates have less of a strong odor, and in many instances would be preferred in stabilizer applications where Patented Nov. 27, 1973 the offensive odor of mercaptides presents a problem. However, the diorganotin dithiocarboxylates have not been successful commercially as have the diorganotin hydrocarbon mercaptides, primarily because of the expensive starting materials required in their preparation.

Heretofore, organotin thiocaboxylates have been prepared by reaction of organotin oxides or halides with thiol acids or their alkali metal salts.

Thus, for example, US. Pat. No. 3,029,267, to Berenbaum et al. dated Apr. 10, 1962 discloses as effective heat stabilizers for vinyl resins dibutyltin dithioacylates having the general formula wherein the Rs represent hydrocarbon radicals, preferably alkyl, aryl and aralkyl, and which are prepared by reaction of dibutyltin oxide with a thiol acid.

The thiol acids used in the preparation of the organotin thiocarboxylates are expensive and difi'icult to prepare, and therefore often unobtainable commercially.

Schumann et .al., J. Organomet-al. Chem., 1964, 97, 98 disclose the preparation of diphenyltin dithiobenzoate by reacting benzoyl chloride with diphenyltin dilithium sulfide.

Netherlands application No. 6703 505 discloses the preparation of diethyltin dithiobenzoate by reacting benzoyl chloride with diethyltin dithiosodium. These are substitution reactions which require removal of alkali halide from the product.

British patent specification No. 1,117,652, dated June 19, 1968, to Albright & Wilson discloses organotin heat stabilizers for vinyl chloride polymers having the formula wherein R is a hydrocarbon group; X is a chlorine or bromine; R is an organic group derived from mercaptan R'SH, an alkyl ester of a mercapto-carboxylic acid, a thio acid or a dithioacid of the carboxylic or phosphoric series; Z is an R, X or SR' group, or an acyloxy group RCO derived from an organic carboxylic acid R"CO H, where R" is a hydrocarbon group. These organotin compounds can be prepared:

(1) by reacting a monoorganotin trihalide or diorganotin halide with an organic mercapto compound (R'SH) in an amount insufiicient to react with all the halogen atoms of the organotin halide and, preferably, in the presence of a tertiary amine as hydrogen halide acceptor, or

(2) by heating the appropriate stoichiometric amounts of an organotin mercaptide of the formula R,,Sn(SR) wherein a is 1 or 2 with at least one tin halide of the formula R SnX wherein b is 0, 1 or 2 at a temperature of from 50 to 200 C. to effect a disproportionation reaction. These procedures provide mixtures of organotin halomercaptides. The distribution of the organotin halomercaptides in such mixtures is dependent only on the proportions of the reactants since these are equilibrium reactions.

In addition, organotin thiocarboxylates are disclosed in Japanese Pat. No. 262,875, published Mar. 12, 1960, which thiocarboxylates are said to be useful in the stabilization of vinyl chloride resins, and have the formula:

wherein R and R are alkyl containing from one to twelve carbon atoms or benzyl, A is a radical represented by the general formula RCOS, B is a radical which can be the same as A or similar to A, but in some cases may be a mercapto or carboxyl residue, and n the number 1 or 2.

U.S. Pat. No. 3,063,963 to Wooten, dated Nov. 13, 1962, discloses stabilizer combinations for vinyl chloride resins consisting of (A) a sulfur compound selected from the group consisting of compounds having one of the following formulae wherein p is an integer of from 1 to 20 and m is an integer of from 2 to 20, and (B) a diorganotin carboxylate which may be partially replaced by a dialkyl tin aliphatic acid salt having the formula wherein R and R are aryl or alkyl groups, and R and R are acid, alcohol, mercaptan, thioacid or other groups, including thioacetate. The method for preparing the organotin thio acid derivative is not disclosed.

THE INVENTION In accordance with the instant invention, it has been determined that diorganotin compounds containing one thiocarboxylate group and one halogen group can be obtained from relatively inexpensive starting materials in a substantially pure form, by reacting a diorganotin sulfide with an acyl halide at a temperature at which reaction proceeds to form a diorganotinmonohalide monothiocarboxylate.

The diorganotinmonohalide monothiocarboxylates are new compounds, and are effective stabilizers in enhancing long term stability as well as enhancing resistance to the development of early discoloration of polyvinyl chloride ICSIHS.

Furthermore, in accordance with the invention, the diorganotinmonohalide monothiocarboxylates are intermediates which can be reacted with active hydrogen compounds such as strong inorganic acids, such as mineral acids, to liberate free thiol acids; or with weak organic acids, such as mercaptans, mercapto acids and esters, thiol acids, carboxylic acids, and alcohols, to form diorganotin monothiocarboxylates containing the same or different functional groups in addition to thiocarboxylate. These diorganotin monothiocarboxylates, are good stabilizers for polyvinyl chdloride resins.

In addition in accordance with the invention, polyvinyl chloride compositions are provided consisting essentially of a polyvinyl chloride resin and a diorganotin thicarboxylate derivative which can be a diorganotin mono halide monothiocarboxylate, or a diorganotin monomercapto acid ester monothiocarboxylate, to enhance resistance of polyvinyl chloride resins to heat deterioration.

THE DIORGANOTIN MONOTHIOCARBOXYLATES The diorganotin monothiocarboxylates in accordance with the invention are diorganotin salts of thiol acids, wherein each tin atom has a valence of four and is linked to two hydrocarbon groups through carbon, and is also linked to one thiocarboxylate group through sulfur, and to one group selected from the group consisting of halide groups, and mercapto acid ester radicals linked to tin through sulfur. Thus, the diorganotin thiocarboxylates of the invention can be defined by the following formula:

LR i tal.

wherein n is one to four, Z is a halide X, which can be fluoride, chloride or bromide, or a mercapto acid ester radical of the type SZ (COC)R as is defined hereinafter. The R groups are hydrocarbon groups linked to tin through carbon, and contain from one to about eighteen carbon atoms, and can be selected from among alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl, alkylcycloalkyl, and cycloalkylalkyl. The preferred R groups are alkyl groups having from one to eight carbon atoms and the most preferred R group has four carbon atoms. The R groups can be the same or difi'erent.

R is an organic group linked to the thiocarboxylate group and is a hydrocarbon group, which can be saturated or unsaturated such as an aliphatic, aromatic, or alicyclic group, or heterocyclic group, containing from one to about thirty carbon atoms, preferably from about one to about twelve carbon atoms, and can be monovalent or polyvalent.

R can contain inert substituents such as halogen, sulfur, hydroxyl or nitro groups. The heterocyclic group includes oxygen or sulfur in the ring, which has from five to seven ring atoms and one or two hetero atoms, the remaining ring atoms being carbons. Thus, R can be alkyl, aryl, alkaryl, arylalkyl, cycloalkyl, alkenyl, alkoxy, alkynyl, furfuryl, tetrahydrofurfuryl, thiophenyl, tetrahydrothiophenyl, or corresponding bivalent radicals when the thiocarboxylate group is derived from a di(thiol acid).

The SZ (COOR group is derived from a mercapto carboxylic acid ester.

m is the number of COOR groups and is an integer from one to four.

R is an organic group derived from a monohydric or polyhydric alcohol having from one to about four hydroxyl groups and from about one to about twelve carbon atoms. If there is more than one COOR group, the R radicals can be the same or different.

Z is a bivalent alkylene radical carrying the S and COOR groups, and in addition can contain free carboxylic acid groups, carboxylic acid salt groups and mercapto groups. The Z radical has from one to about five carbon atoms.

The S-Z -(COOR groups are derived from monoor polymercapto carboxylic acid esters by removal of the hydrogen atom of the mercapto group. These include the esters of aliphatic acids which contain at least one mercapto group, such as, for example, esters of mercaptoacetic acid, (X- and fl-mercaptopropionic acid, aand ,8- mercaptobutyrie acid and aand fl-mercaptovaleric acid, thiomalic acid, 11- and ,B-mercaptoglutaric acid, mercaptomalonic acid, ocand ,B-mercaptoadipic acid and aand ,8- mercaptopirnelic acid, 4-mercaptobutyric acid, w-mercaptohexanoic acid and 4-mercaptocaproic acid.

R is an organic group derived from a monohydric or polyhydric alcohol of the formula R (OH),, where 11 is an integer from one to about four, but is preferably one or two. Thus, R can be alkyl, alkylene, alkenyl, aryl, arylene, mixed alkyl-aryl, mixed aryl-alkyl, cycloaliphatic and heterocyclic, and can contain from about one to about twelve carbon atoms, and can also contain ester groups, alkoxy groups, hydroxyl groups, halogen atoms and other inert substituents. Preferably, R is derived from a monohydric alcohol containing from one to about fifteen carbon atoms, such as methyl, ethyl, propyl, s-butyl, n-butyl, t-butyl, isobutyl, octyl, isooctyl, 2-ethylhexyl, 2-octyl, decyl, lauryl, cyclic monohydric alcohols, such as cyclopropanol, 2,2-dimethyl-l-cyclopropanol, cyclobutanol, 2- phenyl-l-cyclobutanol, cyclopentanol, cyclopentenol, cyclohexanol, cyclohexenol, 2-methyl-, 3-methyl-, and 4- methyl-cyclohexanol, 2 phenyl-cyclohexanol, 3,3,5-trimethyl cyclohexanol, cycloheptanol, 2-methy1-, 3-methyland 4-methyl cycloheptanol, cyclooctanol, cyclononanol, cyclodecanol, cyclododecanol, or from a dihydric alcohol such as glycols containing from two to about fifteen car bon atoms, including ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, tetramethylene gly- 5 col, neopentyl glycol and decamethylene glycol, 2,2,4-trimethyl pentane-diol, 2,2,4,4-tetramethyl cyclobutane-diol, cyclohexane-l,4-dimethanol, and polyols such as glycerine, triethylol propane, mannitol, sorbitol, erythritol, dipentaerythritol, pentaerythritol, and trimethylol propane.

It is not necessary for the alcohol RlOH) to be a single, pure compound. Many of the commercially available and inexpensive alcohol mixtures are suitable and advantageous. The branched-chain primary alcohols made by the x0 process and known as isooctyl, isodecyl and isotridecyl alcohols are mixtures of isomers, but can be used as if they were single compounds. Other alcohol mixtures that can be used include mixed homologous primary alcohols arising from oxidation of the reaction product of ethylene with triethyl aluminum, isomers and homologous secondary alcohols from the hydration of linear C to C olefins or the oxidation of linear C to C paraffins, isomers and homologous straight-chain and methyl-branched primary alcohols resulting from the application of the Oxo process to C to C linear alpha-olefins, homologous mixtures of reaction products from ethylene oxide with alcohols, phenols, or carboxylic acids of the proper carbon content, and the like.

These mercapto acid esters, where not known, can be readily prepared by reaction of the mercaptocarboxylic acid esters with the corresponding organotin oxide or chloride. For a more complete explanation of the process for making, and for additional examples of these diorganotin mercapto ester compounds, see US. Pats. Nos. 2,648,650 to Weinberg et al., 2,641,596 and 2,752,325 to Leistner, and 3,115,509 to Mack, and Canadian Pat. No. 649,989 to Mack.

Where Z is a halide, the diorganotin monothiocarboxylates of the invention are referred to as diorganotinhalide thiocarboxylates. Where Z is a mercapto acid ester group, the diorganotin monothiocarboxylates of the invention are referred to as diorganotin mercapto acid ester thiocarboxylates.

Examples of the diorganotinhalide thiocarboxylates, which can be used as stabilizers in polyvinyl chloride resins, in accordance with the invention, include, but are not limited to:

diethyltinchloride thiobutyrate, dibutyltinchloride thiolaurate, dibutyltinchloride thiostearate, dioctyltinbromide thiocaproate, diisopropyltinfluoride thiotridecanoate, di-Z-ethylhexyltinchloride thiopalrnitate, diphenyltinbromide thioarachidate, ditolyltinfluoride thiopropionate, dicyclohexyltinchloride thioacetate, diisobutyltinchloride thiovalerate, dimethyltinchloride thiopelargonate, diisooctyltinchloride thiohendecanoate, bis[dibutyltinchloride] thioglutarate, bis[dioctyltinbromide] thioadipate, bis[dipropyltinchloride] thiophthalate, bis[dibutyltinchloride] thiomaleate,

bis [diphenyltinchloride] thiosuccinate, bis[di-Z-ethylhexyltiniodide] thioisophthalate, bis[diethyltinchloride] thiopimelate, and bis[dibutyltinchloride] thio-thiodipropionate.

Examples of the diorganotin mercapto acid esters thiocarboxylates in accordance with the invention include, but are not limited to, diethyltin isooctyl thioglycolate thiostearate, dibutyltin isooctyl thioglycolate thiostearate, diisopropyltin 2-ethylhexyl mercapto propionate thiolaurate, di-2-ethylhexyltin tetrahydrofurfuryl mercapto laurate thioacetate, diphenyltin Z-ethylhexyl mercapto butyrate thiocaproate, ditolyltin butoxy ethyl mercapto caproate thiotridecanoate, dimethyltin 2,2-methyl thioglycolate thiovalerate, dicyclohexyltin cyclohexylthioglycolate thiopropionate, diethyltin lauroylthioglycolate 6 thiopalmitate, bis [dibutyltin isooctylthioglycolate] thioglutarate, bis [dioctyltin 2-ethylhexyl mercapto propionate] thioadipate, bis [dipropyltin tetrahydrofurfuryl mercapto stearate]-thiophthalate, bis[diphenyltin 2- ethylhexyl mercapto butyrate] thiosuccinate and bis [dimethyltin 2,2-dimethyl thioglycolate] thiomalate.

MATERIALS FOR THE PREPARATION OF THE DIORGANOTIN MONOTHIOCARBOXYLATES The diorganotin sulfides useful in preparing the diorganotin monohalide monothiocarboxylates of the invention contain groups linked to tin only through carbon, and sulfide sulfur groups, -=S, wherein the sulfide sulfur valences are linked to the same tin atom or to different tin atoms. Each compound contains per tin atom two hydrocarbon or heterocyclic groups linked to tin through carbon.

The diorganotin sulfides useful in this invention can be defined by the following formulae:

In the case of monomers:

R SnS wherein R is a hydrocarbon group linked to tin through carbon, and containing from one to about eighteen carbon atoms. The atomic ratio of sulfur to tin is 1:1. In

the case of polymers:

R II

where n is the number of units in the chain, and ranges up to and more.

Another way of defining the R SnS type is as a trimer:

The Rs are as defined above. The above formulae are not intended to limit the structure of the compound in any way. The structures can be straight chain, branched chain, cyclic, or any combination thereof.

The R hydrocarbon groups in the above formulae can be selected from among alkyl, aryl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, and arylalkyl having from one to eighteen carbon atoms.

The preferred R groups are alkyl groups having from four to eight carbon atoms.

The organotin sulfides used in this invention are well known to the art and can be prepared by a number of procedures described in earlier references which are known to the art. For example, hydrogen sulfide can be bubbled at about 40 C. into a slurry of hydrocarbontin oxide in water or an organic solvent (such as methanol, acetone, or toluene). The insoluble oxide is converted to a solution or dispersion of the sulfide and the reaction is terminated when the entire system is liquefied.

Another useful technique is the displacement of hydrocarbontin halide (e.g. Bu SnCl by an aqueous alkali metal sulfide or ammonium sulfide. Hydrocarbontin sulfides also can be prepared from the interaction of hydrocarbontin halide with sulfur compounds other than sulfides, such as sodium thiosulfite and ammonium polysulfide. These reactions provide unstable intermediates that decompose to the hydrocarbontin sulfide plus another product characteristic of the particular starting materials, e.g. alkali metal sulfite or free sulfur.

All the above preparative methods can be summarized in the transformations below, where the di-n-butyltin compounds shown are representative of the entire class of organotin compounds:

When these preparations are carried out in an aqueous medium, a small proportion of the sulfur atoms in the hydrocarbontin sulfides are replaced by oxygen atoms, resulting in sulfur-deficient products having average compositions represented by the empirical formula where p is at least 0.85.

In the process of this invention, these sulfides may be used in preparing the diorganotin monohalides monothiocarboxylates, and provide stabilizers for polyvinyl chloride resins as effective as the oxygen-free sulfides, and wherever organotin sulfides are mentioned the term is intended to include both the pure compounds and the sulfurdeficient preparations.

There are many other procedures for the preparation of these compounds. The above list of procedures is not intended to be exhaustive. Organotin sulfides prepared by any other procedure would also be useful in the present combination.

The R groups linked to tin through carbon can, for example, be methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, amyl, hexyl, octyl, 2-ethylhexyl, isooctyl, phenyl, benzyl, oumyl, tolyl, xylyl, cyclohexyl, cyclopentyl, n-decyl, n-dodecyl, hexadecyl and octadecyl.

Examples of organotin sulfides are dipropyltin sulfide, dibutyltin sulfide, di-n-pentyltin sulfide, dihexyltin sulfide, di-Z-ethylhexyltin sulfide, di(isobutyl)tin sulfide, di(noctyltin) sulfide and dimethyltin sulfide, di(isoamyl)tin sulfide, diisohexyltin sulfide, di-2-ethyl butyltin sulfide, didodecyltin sulfide, and dioctadecyltin sulfide.

The above compounds can have any degree of polymerization falling within the above formula.

Preferred examples of organotin sulfides are dibutyltin sulfide and dioctyltin sulfide.

The acyl halides useful in this invention can be defined by the formula:

n is one to four, X is a halide and can be chloride, bromide, or fluoride, preferably chloride, and R can be a monovalent or polyvalent organic radical containing from one to about thirty carbon atoms such as an aliphatic, aromatic, alicyclic or heterocyclic radical. Where It is one, R is monovalent and can be an organic group such as alkyl, aryl, alkaryl, arylalkyl, cycloalkyl, al'kenyl, alkylcycloalkyl, cycloalkylakyl and heterocyclic. Thus, R can be methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, hexyl, isohexyl, heptyl, octyl, isooctyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl, stearyl, butenyl, prophenyl, phenyl, naphthyl, benzyl, phenethy], methoxyphenyl, hydroxyphenyl, cyclohexyl, cyclopentyl, ethylcyclohexyl, cyclopentylmethyl, and tetrahydrofurfuryl.

Where n is two or greater, R is a bivalent or polyvalent radical and can correspond to any of the abovementioned monovalent radicals and can be, for example, alkylene, arylene, or cycloalkylene such as R may also have other inert substituents attached to the hydrocarbon group as for example, ether, thioether and halogen groups such as:

PROCESS OF THE INVENTION The diorganotinmonohalide monothiocarboxylates can be prepared by reaction of a diorganotin sulfide and an acyl halide as discussed hereinbefore.

In carrying out the process of the invention for preparing the diorganotinmonohalide monothiocarboxylates, the diorganotin sulfide is reacted with the acyl halide. The reaction is exothermic. The reaction mixture is maintained at a temperature within the range from about 30 to about 200 0, preferably from about 50 to about C. A diluent such as toluene, benzene or xylene can be used, but is usually unnecessary. When the addition of the diorganotin sulfide is completed, the reaction is essentially complete. However, heating can be continued for another one to three hours, to insure that all of the diorganotin sulfide has reacted, but longer heating times up to about five hours can be used, if desired. The reaction can be expressed by the following equation:

where R, R and X are as defined heretofore.

The diorganotin sulfide and acyl halide are employed in an equivalent ratio, but other ratios can be used which will give mixtures of diorganotin monohalomonothiocarboxylate and excess starting reactant.

When a stoichiometrically equivalent ratio of diorganotin sulfide and acyl halide are employed, the reaction product does not need any purification or separation since the reaction is an addition reaction. The diorganotinmonohalide monothiocarboxylates are completely compatible with polyvinyl chloride resins in the proportions required for stabilizing effectiveness.

The diorganotin halide thiocarboxylate can be further reacted With active hydrogen compounds. These active hydrogen compounds can be weak organic acids and their metal salts or strong inorganic acids.

Where the diorganotinmonohalide monothiocarboxylate is to be further reacted with an active hydrogen compound, the reaction mixture containing the diorganotinhalide thiocarboxylate can be employed as is so that the active hydrogen compound can be added directly to such reaction mixture, or, if desired, the diorganotinhalide thiocarboxylate can be separated from any unreacted material, by conventional techniques, for example, solventextraction, and the substantially pure product can be reacted with the active hydrogen compound.

Normally, the diorganotinhalide thiocarboxylate is employed in an equimolar ratio to the active hydrogen compound. Other molar ratios will provide an excess of one of the reactants in admixture with the product.

The reaction temperatures employed in reacting the diorganotinhalide thiocarboxylates and the active hydrogen compound depends upon the type of active hydrogen compound employed. Reaction temperatures ranging from below room temperature up to about 200 C., and preferably, within the range from about 30 to about 150 C. are satisfactory.

The diorganotinhalide thiocarboxylates can be reacted with strong inorganic acids to liberate free thiol acids of the formula R COSH, wherein R is as defined hereinbefore. Examples of such strong acids include, but are not limited to, hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, sulfurous acid, and phosphoric acid.

The liberated thiol acid can then be recovered from the mixture by conventional separation techniques, such as distillation, or solvent extraction. This is a useful process for preparing thiol acids from acyl halides.

In addition, the diorganotinmonohalide monothiocarboxylates can be reacted with weak organic acids such as organic carboxylic acids, alcohols, or mercaptans, which can be represented by the formula:

R is a hydrocarbon radical having from one to about thirty carbon atoms similar to R or acyl radical having the formula or a Z COOR group (as defined hereinbefore), R is a hydrocarbon radical having from one to about thirty carbon atoms, similar to R or a Z --COOR group. R is hydrogen or a metal capable of forming a salt with [HA] R R is an organic group derived from a monohydric or polyhydric alcohol, A is oxygen or sulfur, and R A represents the group reactive with the halide of the diorganotinhalide thiocarboxylate, the R group becoming attached to tin through A or its equivalent.

Thus, the active hydrogen compound can be a mercaptan of the formula R SH. Examples of such mercaptans include methyl mercaptan, ethyl mercaptan, propyl mercaptan, isopropyl mercaptan, butyl mercaptan, isobutyl mercaptan, n-hexyl mercaptan, cyclohexyl mercaptan, phenyl mercaptan, benzyl mercaptan, oleyl mercaptan and lauryl mercaptan.

In addition, the active hydrogen compound can be a mercapto acid ester of the formula HSZ (COOR such as isooctyl thioglycolate, di-n-butylthiomalate, 2- ethylhexyl mercapto propionate, cyclohexyl-mercapto propionate, Z-ethylhexyl mercapto butyrate, tetrahydrofurfuryl a-mercapto laurate, butoxy ethyl tit-mercapto caproate, 2,2-dimethyl propyl thioglycolate, cyclohexyl thioglycolate, lauryl thioglycolate, isooctyl mercapto propionate, methyl a-mercapto laurate, ethylene glycol thioglycolate, butyl mercapto propionate, and issoctyl thiomalate.

The active hydrogen compound can be an alcohol of the formula R (OH) Examples of typical alcohols are set out hereinbefore with respect to the R (Ol-I) alcohols.

The thiol acids which can be reacted with the diorganotinhalide thiocarboxylates, has the formula wherein R and n are as defined hereinbefore and include, but are not limited to, thioacetic acid, thiopropionic acid, thiobutyric acid, thiovaleric acid, thiocaproic acid, thiopelargonic acid, thiocaprylic acid, thiocapric acid, tholauric acid, thiomyristic acid, thiopalmitic acid, thostearic acid, thiobenzoic acid, thio Z-naphthoic acid, thiocyclohexane acetic acid, dithioadipic acid, dithiosuccinic acid, dithioglutaric acid, dithiopimelic acid, dithiobrassylic acid, dithiophthalic acid, dithioisophthalic acid, 2-octenedithioic acid, dithio-2,S-heptadienedioic acid, 1,4-cyc lohexene dithiocarboxylic acid, and thiol trimellitic acid.

The active hydrogen compound can be a carboxylic acid of the formula R [COOH],, wherein R and n are as defined hereinbefore. Examples of such acids include, but are not limited to, acetic acid, propionic acid, butyric acid, lauric acid, myristic acid, palmitic acid, stearic acid, cyclohexane carboxylic acid, benzoic acid, succinic acid, chloropropionic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, trimelletic acid, maleic acid, phthalic acid, isophthalic acid, sorbic acid, thiodipropionic acid, 3-butenoic acid. In addition, partial esters of the above polyvalent carboxylic acids with any of the R (OH) alcohols discussed hereinbefore can also be employed.

To illustrate this process, diorganotin(mercapto acid ester)thiocarboxylates can be prepared by reacting a diorganotin sulfide and an acyl halide to form a diorganotinhalide thiocarboxylate (in accordance with the reaction i (11 8118) X IL R Basin-SO R where R, R n and X are as defined heretofore) and further reacting this with a mercapto acid ester, in accordance with the following reaction:

wherein R, R R Z and n are as defined hereinbefore.

POLYVINYL CHLORIDE RESIN COMPOSITIONS The diorganotinhalide thiocarboxylates and the diorganotin mercapto acid ester thiocarboxylates are effective in enhancing resistance of any polyvinyl chloride resin to deterioration upon exposure to heat. The term polyvinyl chloride as used herein is inclusive of any polymer formed at least in part of the recurring group a. fl

and having a chlorine content in excess of 40%. In this group, the X groups can each be either hydrogen or chlorine. In polyvinyl chloride homopolymers, each of the X groups is hydrogen. Thus, the term includes not only polyvinyl chloride homopolymers but also after-chlorinated polyvinyl chlorides such as those disclosed in British Pat. No. 893,288 and also copolymers of vinyl chloride in a major proportion and other copolymerizable monomers in a minor proportion, such as copolymers of vinyl chloride and vinyl acetate, copolymers of vinyl chloride with maleic or fumaric acids or esters, and copolymers of vinyl chloride with styrene, propylene, and ethylene. The invention also is applicable to mixtures of polyvinyl chloride in a major proportion with other synthetic resins such as chlorinated polyethylene or a copolymer of acrylonitrile, butadiene and styrene. Among the polyvinyl chlorides which can be stabilized are the uniaxially-stretch oriented polyvinyl chlorides described in US. Pat. No. 2,984,593 to Isaksem et al., that is, syndiotactic polyvinyl chloride, as well as atactic and isotaetic polyvinyl chlorides.

The stabilizers of this invention, including, if desired, supplementary stabilizers, are excellent stabilizers for both plasticized and unplasticized polyvinyl chloride resins. Supplementary stabilizers such as phenolic antioxidants, thiodipropionic acid esters, organic mono or polysulfides, triphosphites, and aromatic amines, all of which are disclosed in U.S. Pat. No. 3,398,114, dated Aug. 20, 1968; epoxy compounds such as described in US. Pat. No. 2,997,454; and on and ,9 mercapto acids, such as thiolactic acid and fi-mercaptopropionic acid can be employed. In addition, other metallic stabilizers can be employed, such as organotin compounds, polyvalent metal salts of carboxylic acids and phenols such as salts of calcium, tin, cadmium, barium, zinc, magnesium and strontium can be used.

When plasticizers are to be employed, they may be incorporated into the polyvinyl chloride resins in accordance'with conventional means. The conventional plasticizers can be used, such as dioctyl phthalate, dioctyl sebacate and tricresyl phosphate. Where a plasticizer is employed, it can be used in an amount within the range from to 100 parts by weight of the resin.

Particularly useful plasticizers are the epoxy higher esters having from about twenty to about one hundred fifty carbon atoms. Such esters will initially have had unsaturation in the alcohol or acid portion of the molecule, which is taken up by the formation of the epoxy group.

Typical unsaturated acids are oleic, linoleic, linolenic, erucic, ricinoleic and brassidic acids, and these may be esterified with organic monohydric or polyhydric alcohols, the total number of carbon atoms of the acid and the alcohol being within the range stated. Typical monohydric alcohols include butyl alcohol, 2-ethylhexyl alcohol, lauryl alcohol isooctyl alcohol, stearyl alcohol, and oleyl alcohol. The octyl alcohols are preferred. Typical polyhydric alcohols include pentaerythritol, glycerol, ethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, neopentyl glycol, ricinoleyl alcohol, erythritol, mannitol and sorbitol. Glycerol is preferred. These alcohols may be fully or partially esterified with the epoxidized acid. Also useful are the epoxidized mixtures of higher fatty acid esters found in naturally-occurring oils such as epoxidized soybean oil, epoxidized olive oil, epoxidized cottonseed oil, epoxidized tall oil fatty acid esters, epoxidized linseed oil and epoxidized tallow. Of these, epoxidized soybean oil is preferred.

The alcohol can contain the epoxy group and have a long or short chain, and the acid can have a short or long chain, such as epoxy stearyl acetate, epoxy stearyl stearate, glycidyl stearate, and polymerized glycidyl methacrylate.

A small amount, usually not more than 1.5%, of a parting agent or lubricant, also can be included. Typical parting agents are the higher aliphatic acids, and salts having twelve to twenty-four carbon atoms, such as stearic acid, lauric acid, palmitic acid and myristic acid, lithium stearate and calcium palmitate, mineral lubricating oils, polyvinyl stearate, polyethylene and parafiin wax.

Impact modifiers, for improving the toughness or impact-resistance of unplasticized resins, can also be added to the resin compositions stabilized by the present invention in minor amounts of usually not more than 10%. Examples of such impact modifiers include chlorinated polyethylene, ABS polymers, and polyacrylate-butadiene graft copolymers.

The diorganotin monothiocarboxylate stabilizers of the invention, are employed in an amount sutficient to impart the desired resistance to heat deterioration at working temperatures of 350 F. and above. The longer the time and the more rigorous the conditions to which the resin will be subjected during working and mixing, the greater the amount required. Generally, as little as 0.25% total of the stabilizer by weight of the resin, will improve resistance to heat deterioration.

There is no critical upper limit on the amount, but amounts above about 15% by weight of the resin do not give an increase in stabilizing effectiveness commensurate with the additional stabilizer employed. Preferably, the amount is from about 0.5 to about 5% by Weight of the resin.

The diorganotin monothiocarboxylate stabilizers of the invention are extremely effective when used alone, but they can be employed together with other polyvinyl chloride resin stabilizers, if special effects are deisred. The stabilizer combination of the invention in this event will be the major stabilizer, and the additional stabilizer will supplement the stabilizing action of the former, the amount of the stabilizer combination being within the range from about 0.25 to about 15 parts by weight per parts of the resin, and the additional stabilizer being in an amount of from about 0.05 to about 10 parts per 100 parts of the resin.

The diorganotin monothiocarboxylates can be employed in various combinations. Examples of combinations of the diorganotin thiocarboxylates include the diorganotin mercapto acid ester thiocarboxylate and/or diorganotinhalide thiocarboxylate and/or diorganotin alcoholate thiocarboxylate, and/or diorganotin mercaptide thiocarboxylate, and/or diorganotin dithiocarboxylate and/or free thiol acid. In some cases, an enhanced synergistic stabilizer activity is observed in such combinations.

A stabilizer composition in accordance with this invention can be prepared by mixing the diorganotin monothiocarboxylate and any supplemental stabilizers With any liquid lubricant or plasticizer to be added to the resin composition with the stabilizer.

The preparation of the polyvinyl chloride resin composition is easily accomplished by conventional procedures. The selected stabilizer combination is formed as above, and then is blended with the polyvinyl chloride resin, or alternatively, the components are blended individually in the resin, using, for instance, a two or three roll mill, at a temperature at which the mix is fluid and thorough blending facilitated, milling the resin composition including any plasticizer at from 250 to 375 F. for a time suflicient to form a homogeneous mass, usually five minutes. After the mass is uniform, it is sheeted off in the usual way.

For the commercial processing of rigid polyvinyl chloride, the stabilizer is conveniently mixed with all or a portion of the polymer to be stabilized with vigorous agitation under such conditions of time and temperature that the stabilizer is sufficiently imbibed by the polymer to produce a dry, free-flowing powder. The well-known Henschel mixer is well suited to this procedure.

The following examples relate to the preparation and testing of diorganotinhalide thiocarboxylates and other diorganotin thiocarboxylates in accordance with the invention.

EXAMPLE 1 Dibutyltin sulfide (132.5 g., 0.5 mole) was slowly added with stirring to lauroyl chloride (109.3 g., 0.5 mole) in a flask. The reaction was exothermic and the rate of addition of the dibutyltin sulfide was regulated to maintain the temperature of the mixture at about 60 C. When all of the dibutyltin sulfide had been added, the mixture was heated at 100 C. for three hours, and cooled. A yellow liquid was obtained which did not have any odor of lauroyl chloride. This product was dibutyltin monochloride monothiolaurate.

EXAMPLE 2 Dibutyltin sulfide (142.5 g.) was slowly added to stearoyl chloride (163.5 g.). During the addition of the dibutyltin sulfide, the mixture was maintained between 60 to 70 C. After addition of the dibutyltin sulfide was complete, the reaction mixture was stirred for three hours at 100 C. n cooling, a yellow semi-solid dibutyltin monochloride monothiostearate formed.

EXAMPLE 3 Isophthaloyl chloride (191.5 g.) was melted and dibutyltin sulfide (500 g.) was slowly added thereto with stirring, while maintaining the temperature between 70 and 80 C. After the addition was completed, the product was heated for three hours at 100 C. and then poured onto aluminum foil. Upon cooling, the product solidified. The product was his [dibutyltinmonochloride]thioisophthalate.

EXAMPLE 4 Dibutyltin sulfide (178.7 g.) was slowly added to adipoly chloride (61 g.) at room temperature. The temperature of the reaction rose to about 90 C. and was kept at 90 C. for about three hours. The bis [dibutyltinchloride] thioadipate product solidified on standing three to four days.

EXAMPLE 5 To 120.9 grms. of dibutyltin monochloride monothiolaurate prepared as in Example 1, there was added 200 ml. of water and the mixture was stirred and heated at 50 C. Isooctyl thioglycolate (51 g., 0.25 mole) was then added. Sodium hydroxide g.) dissolved in 30 ml. water was slowly added to the mixture and the temperature maintained at about 50 C. At the completion of the sodium hydroxide addition, hexane (100 ml.) was added to the mixture. Two phases formed, an upper hex ane phase and a lower aqueous phase. The aqueous phase was removed from the hexane phase, which was washed with water, and stripped of hexane under vacuum. The product dibutyltin monoisooctyl thioglycolate monothiolaurate was a yellow liquid weighing 155 g. and analyzed 18.25% Sn and 9.8% S.

EXAMPLE 6 Dibutyltin sulfide (66.0 g.) was slowly added to stearoyl chloride (75.9 g.), while maintaining the mixture between 60 and 70 C. After addition of the dibutyltin sulfide was complete, the mixture was stirred for three hours at 100 C. Water (200 ml.) was added and the mixture was maintained at 70 C. with stirring. Thereafter isooctyl thioglycolate (51 g.) was added. Sodium hydroxide (10 g. in 30 ml. water) was then added dropwise to the mixture while maintaining the mixture at 70 C. On cooling, hexane (about 300 ml.) was added, thereby causing the mixture to separate into an aqueous lower layer, a

hexane upper layer, and a third layer at the interface. The aqueous lower layer was separated and the upper phases washed with water, charged into a flask and dried at 100 C. A yellow product dibutyltin monoisooctyl thioglycolate monothiostearate formed weighing 182 g. weighing 182 g. The product analyzed 16.1% Sn and 4.4% S.

EXAMPLE 7 Bis(dibutyltinmonochloride)thioadipate (142.6 g.) as prepared in Example 4, was suspended in water (300 ml.) at 50 C. Isooctyl-3-mercaptopropionate (87.2 g.) and sodium hydroxide (16 g.) dissolved in water (25 ml.) was added dropwise and the mixture was maintained at 55 C. for 2 hours. The upper (aqueous) layer was decanted, and the lower (organic) layer washed with water and dried under vacuum at 100 C. A yellow product bis [dibutyltin(isooctyl-3-mercaptopropionate)] thioadipate (210 g.) was produced which analyzed 22.6% Sn and 6.2% S.

EXAMPLE 8 Dibutyltin sulfide (132.5 g., 0.5 mole) was added to lauroyl chloride 109.3 g., 0.5 mole) which was stirred and maintained at 60 C. When addition of the dibutyltin sulfide was completed, the mixture was heated at 100 C. for about three hours. Thereafter, sodium methoxide (13.5 g., 0.25 mole) was slowly added to the mixture. The reaction mixture was stirred for one hour at C. Water was added and the mixture stirred. The aqueous phase was removed. The organic layer was washed with water and dried.

The reaction product dibutyltin methylate thiolaurate analyzed 24% Sn and 6.7% S.

EXAMPLE 9 Dibutyltin sulfide (132.5 g., 0.5 mole) was added to lauroyl chloride (109.3 g., 0.5 mole) which was stirred and maintained at 60 C. When addition of the dibutyltin sulfide was completed, the mixture was heated at C for about three hours.

Water (200 ml.) was added to 120.9 g. of the above reaction mixture and the mixture was warmed to about 50 C. Thereafter, isooctyl maleate (57 g., 0.25 mole) was added to the mixture. A solution of sodium hydroxide 10 g. in 30 ml. water) was slowly added and the reactron mixture was stirred for two hours at 60 C. The organic phase was separated, washed with additional water and dried.

The reaction product dibutyltin isooctyl maleate thiolaurate analyzed 17.6% Sn and 4.6% S.

EXAMPLE 10 Dibutyltin sulfide (132.5 g., 0.5 mole) was added to lauroyl chloride (109.3 g., 0.5 mole) which was stirred and maintained at 60 C. When addition of the dibutyltin sulfide was completed, the mixture was heated at 100 C. for about three hours.

Water (200 ml.) was added to 120.9 g. of the above reaction mixture and the mixture was warmed to about 50 C. Thereafter, maleic acid (14.5 g., 0.125 mole) was added to the mixture and a solution of sodium hydroxide (10 g. in 30 ml. water) was slowly added. The reaction mixture was stirred for 3 hours at 60 C.

The reaction product bis[dibutyltin thiolaurate] maleate analyzed 23.5% Sn aud 6.3% S.

EXAMPLE l1 Dibutyltin sulfide (132.5 g., 0.5 mole) was added to lauroyl chloride (109.3 g., 0.5 mole) which was stirred and maintained at 60 C. When addition of the dibutyltin sulfide was completed, the mixture was heated at 100 C. for about three hours.

Water (200 ml.) was added to 120.9 g. of the above reaction mixture and the mixture was warmed to about 50 C. Thereafter, ,B-mercaptopropionic acid (13.25 g.,

0.125 mole) was added to the mixture and a solution of The thiolauric acid recovered from the organic phase sodium hydroxide (10 g. in ml. water) was added eighed 91 g. and had a sulfur content of 14.5%. zltogvyghe reaction mlxture was stirred for two hours EXAMPLES I to Iv The reaction product bis[dibutyltin thiolaurate] mer- A series of P vinyl chloride resin compositions were captopropionate analyzed 23.9% Sn and 9.5% S. P P having the following composition! EXAMPLE 12 Parts by weight Diamond 450 polyvinyl chloride resin homopoly- Di-n-octyltin sulfide (188.5 g., 0.5 mole) was added to 46 g. (0.5 mole) propionyl chloride which was stirred and maintained at 50 C. When addition of dioctyltin sulmer e--. 100 10 Stabilizeras shown in Table I.

fide was completed, the mixture was stirred for one hour The compon were blended, the resulting mixture at C. Dry hydrogen chloride w bubbled i t th was compounded and milled on a two-roll mill at 350 F. mixture and thiolpropionic acid was distilled out. 35.5 g. for five minutes, She and out into p and the of thiolpropionic acid was recovered, B.P. 108-110" C strips heated in an oven at 375 F. and 350 F.

TABLE I (350 F.)

Stabilizer composition (parts) Ex. IIDibutyltin mono- Ex. III-Dibutyltin mono- Ex. IV-Dibutyltln mono- Ex. I-Dibutyltin monothiolaurate monoisooctyl thiolaurate monoisooetyl thiolaurate monoisooetyl Control A thiolaurate monoisooetyl thioglyeolate (Ex. 6), 4.4; thioglycolate (Ex. 6), 4.4: thioglyeolate (Ex. 5), 4.4; No stabilizer thioglyeolate (Ex. 5), 4.5 thiolatic acid, 0.1 zmc octoate, 0.1 stannous octoate, 0.1

Time (minutes) Color Initial Colorless- Colorless Cnlnrlo s C m Colorless. 1 d Very pale yellow do do Do. 30 Pale yellow do Very pale yellow Very pale yellow.

Light yellow dn do Do. Yellow dn Pale yellow Do.

do Very faint yellow tint do Pale yellow. do Very pale yellow Light yellow Light yellow.

do 0 do Do, do Pale yellow Do.

Initial Colorless Colorless Colorless Colorless 15 Dark red Yellow do i Pale yellow- 3 do Colorless-yellow tint do 4s 1 do Very pale yellow do on do Pale yellow. do Do. do rlo Light yellow Light yellow. do Light yellow- Yellow Do. Yellow-brown edges Yellow-brown edges Yellow-brown edges Yellow-brown. (in (in Brown D0.

n 1.4663. The distillation residue was identified as di-n- It is apparent from the data in Table I, that the dibuoctyltin dichloride, 40 tyltin monoisooctyl thloglycolate monothlolaurate significantly improves the resistance of polyvinyl chloride EXAMPLE 13 resin to discoloration. Furthermore, as seen in Examples II to IV, thiolactic acid, zinc octoate, and stannous ocgg g gi g 25i 23 i l f toate, respectively, significantly improve the effectiveness m e l y c o 1 W 1 e S lmng e 45 of the dibutyltin isooctyl thioglycolate thiostearate in intempemtur? mamtfimed at 100 Upon completion hibiting development of early discoloration in the polyof the addition the mlxture was stirred for 5 hours at vinyl chloride resim 100 C. 100 ml. conc. HCl was added to the mixture which was stirred for another hour at 80 0. Then 200 ml. EXAMPLES V AND VI of Water Was added, With Stirring- The aqueous Phase Was 50 A series of polyvinyl chloride resin compositions were separated. The organic phase was diluted With 100 ml. prepared having the same formulations as Examples I to of hexane and washed with water and dried under vacuum. IV except for the stabilizers which are shown in Table II.

TABLE II (350 F.)

Stabilizer composition (parts) Ex. VI.Dibutyltin mono- Ex. V.--Dibutyltin monothiostearate monoisooetyl- Control A- thiostearatemonoisooctylthloglycolate (Ex. 6), 5.1; No stabilizer thioglycolate (Ex. 6), 5.2 thiolactic acid, 0.1

Time (minutes) Color Colorless Colorless Colorless.

Do. Yellow-brown edges.

17 18 It is apparent from the data in Table II that the di- The data in Table IV shows that the bis[dibutyltin butyltin monoisooctyl thioglycolate monothiastearate enmonoisooctyl-3-mercaptopropionate] thioadipate is elfechances the resistance of the polyvinyl chloride resin to the tive in enhancing resistance of polyvinyl chloride resin development of color on heating. Furthermore, as seen in to discoloration due to exposure to heat, and that di- Exarnple VI, t o fi d significantly improves the 5 butyltin oxide enhances the heat stability even further. effectiveness of the dibutyltin monoisooctyl thioglycolaate Th c mbination of bis[dibuty1tin m0noisooctyl-3- monothiostearate in inhibiting development of early dismercapto propionate] thioadipate with dibutyltin oxide coloratlon in the polyvlnyl Ch r r and stannous octoate enhances even further the resistance EXAMPLES VII AND VIII of the polyvinylchloride resin to early discoloration. Polyvinyl chloride resin compositions of the following EXAMPLE XII formulation were Prepared Dibutyltin monothiolaurate monoisooctyl maleate of Parts by weight Example 9 was tested in the polyvinyl chloride resin Polyvinyl chloride homopolymer (Diamond 40) 100 B1611 dex 401 10 formulation of Example XI and the results indicated that Wax E, lubricant 0.25 it was an effective heat stab1l1zer. Stabilizer-as shown in Table III. EXAMPLE XIII The above formulation Was blended, and the resu g Bis[dibutyltin monothiolaurate] fl-mercapto propionate mixture was milled and heated on a two-roll mill at 350 of Example 11 was tested in the polyvinyl chloride resin F. for five minutes, and ten sheeted ofl. The resulting 2O composition of Example XI. The results indicate that sheet was cut into strips, and the strips were tested in an this material is an eifective stabilizer for polyvinyl chlooven at 375 F. ride.

TABLE III (375 F.)

Stabilizer combination (amount) Ex. VII-Bis[dibuty1tinmonochloride] thioiso- Control A-No monochloride] thioiso- Control B-Monobutyltinphthalate (Ex. 3), (1.15);

stabilizer phthalate (Ex. 3), (2.0) sulfide, (2.0) monobutyltin sulfide, (0.3)

Time (minutes) Color Initial Colorless Colorless Colorless Colorless. 15 Dark red Yellow Light tau Pale tan. do T n Light tan 45. Dark yellow Do. 60 Amb Do.

Tan.

90 Brown. Black-brown. Light brown. 105 do Black Dark brown.

The data with respect to Examples VII and VIII shows EXAMPLE XIV that bis[dibutyltinmonochloride] thioisophthalate is, in eifect, a heat stabilizer. Furthermore, the data of Example VIH shows that the combination with monobutyltin sulfide enhances the effectiveness of the bis[dibutyltin- Dibutyltin monochloride monothiolaurate of Example 1 was tested as a stab1l1zer 111 a polyvinyl chloride resin composition of Example XI and found to be an efiective monochloride] thioisophthalate as a heat stabilizer for stab1l1zer EXAMPLE XV polyvinyl chloride resin. D b l h 1 th 1 f E 1 i uty tin monomet y ate mono io aurate o xamp e E XAMP LES IX Q 8 was tested in a polyvinyl chloride resin composition of Polyvinyl chlonde resm Composmons were Prepared Example XI and found to be an effective heat stabilizer.

having the following formulation: Having regard to the foregoing disclosure, the follow- Parts by Weight ing is claimed as the inventive and patentable embodi- Diamond 40, polyvinyl chloride resin homoments thereof:

Polymer 100 1. A process for preparing diorganotinmonohalide Blendex 401, acrylonitrile-butadiene-styrene monothiocarboxylates having the for la copolymer 10 R Wax E, lubricant 0.25 Stabilizer-as shown in Table IV. The ingredients were blended, and the resulting mix- R Z n ture was compounded and heated on a two-roll mill at wherein n is a number within the range from one to four, 350 F. for five m u sheeted and Cut 111110 p X is halide, R is a hydrocarbon group having from one and heated in an oven at 375 F. The results are tabulated to about eighteen carbon atoms, and R is an organic in Table IV group having from one to about thirty carbon atoms, TABLE W (375 F.)

Stabilizer composition (parts) Ex. XI-Bisldibutyltin- Ex. X-B1s[d1butyltinmonoisooctyl mercapto Ex. lx -Blsldlblltyltlnmonoisooctyl mercaptopropionate1thioadipate monoisooctyl mercaptopropionate] thioadipate (Ex. 7) 0.84; dibutyltin Control C-Dlpropionate] thioadlpate (E x. 7), .12; dibutyltin oxide, 039; stannous butyltin oxide, (Ex. 7), 1.68 oxide, 0.26 octoate, 0.02 1.68 Control A-No Time (minutes) stabilizer Color Initial Colorless Colorless. Colorless c 1 15 Dark red Yellow Light yellow Pale yellow 0 Mess do... -do .do do Light brown. Red brown which comprises reacting a diorganotin sulfide having at least one sulfur atom linked directly to tin, the remaining radicals being R hydrocarbon groups linked to tin through carbon and having from one to about eighteen carbon atoms, with an acyl halide having the formula Elia] wherein X is halide, R is an organic group having from one to about thirty carbon atoms, and n is a number within the range from one to four, at a temperature at which reaction proceeds to form the diorganotinmonohalide monothiocarboxylate.

2. A process in accordance with claim 1 in which the diorganotin sulfide has a formula selected from the group consisting of R SnS and wherein R is a hydrocarbon group linked to tin through carbon and containing from one to about eighteen carbon atoms, and n is a number representing the number of polymeric units in the chain.

3. A process for preparing a thiol acid having the formula R COSH, wherein R is an organic group having from one to about thirty carbon atoms, which comprises reacting an acyl halide having the formula wherein X is halide, R is an organic radical having from one to about thirty carbon atoms, and n is a number within the range from one to four, and a diorganotin sulfide having at least one sulfur atom linked directly to tin, the remaining groups being linked to tin being R hydrocarbon groups linked to tin through carbon and having from one to about eighteen carbon atoms to form a diorganotin halide thiocarboxylate in accordance with claim 1, and then reacting the diorganotinhalide thiocarboxylate with a strong inorganic acid to liberate the corresponding thiol acid.

4. A process for preparing diorganotin thiocarboxylates having the formula R I: SnSC-:| R 1/; ii

wherein n is a number within the range from one to four, Z is selected from the group consisting of SR Z1( )m OOCR and -OR R is an organic group having from one to about thirty carbon atoms, R is a hydrocarbon group having from one to about thirty carbon atoms, m is the number of COOR groups and is within the range from one to about four, R is an organic group derived from an alcohol selected from the group consisting of monohydric and polyhydric alcohols having from one to about four hydroxyl groups and from one to about twelve carbon atoms, and Z is selected from the group consisting of bivalent alkylene radicals having from one to about five carbon atoms and such radicals having a substituent selected from a free carboxylic acid group, a carboxylic acid salt group, and a mercapto group, which comprises reacting an acyl halide having the formula Elia],

wherein X is halide, R is an organic radical having from one to about thirty carbon atoms, and n is a number within the range from one to four, with a diorganotin sulfide having at least one sulfur atom linked directly to 20 tin, the remaining groups being linked to tin being R hydrocarbon groups linked to tin through carbon and having from one to about eighteen carbon atoms to form a diorganotinhalide thiocarboxylate in accordance with claim 1, and then reacting the diorganotinhalide thiocarboxylate with an active hydrogen compound selected from the group consisting of strong inorganic acids, mercaptans R SH, mercapto acid esters HS-Z (COOR thiol acids R, if SH) carboxylic acids R (COOH),, carboxylic acid esters R(COOR and alcohols R (OH-; wherein R Z R and m are as above, and n is a number within the range from one to about four, to form a diorganotin thiocarboxylate.

5. A process for preparing diorganotin monomercapto acid ester monothiocarboxylates having the formula SnSC- -ZlcooR- n wherein n is a number within the range from one to about four, In is the number of COOR groups and is within the range from one to about four, R is an organic group derived from an alcohol selected from the group consisting of monohydric and polyhydric alcohols having from one to about four hydroxyl groups and from one to about twelve carbon atoms, and Z is selected from the group consisting of bivalent alkylene radicals having from one to above five carbon atoms and such radicals having a substituent selected from a free carboxylic acid group, a carboxylic acid salt group, and a mercapto group, which comprises reacting an acyl halide having the formula Elisa] wherein X is halide, R is an organic radical having from one to about thirty carbon atoms, and n is a number within the range from one to four, with a diorganotin sulfide having at least one sulfur atom linked directly to tin, the remaining groups being linked to tin being R bydrocarbon groups linked to tin through carbon and having from one to about eighteen carbon atoms, to form a diorganotinhalide thiocarboxylate in accordance with claim 1, and then reacting the diorganotinhalide thiocarboxylate with a mercapto acid ester having the formula HSZ1-( )m to form the diorganotin mercapto acid ester thiocarboxylate.

6. A process for preparing a diorganotin mercaptide thiocarboxylate having the formula wherein n is a number within the range from one to about four, R is an organic radical having from one to about thirty carbon atoms, and R is a hydrocarbon group having from one to about thirty carbon atoms, which comprises reacting an acyl halide having the formula Elia],

wherein X is halide, R is an organic radical having from one to about thirty carbon atoms, and n is a number within the range from one to four, with a diorganotin sulfide having at least one sulfur atom linked directly to tin, the remaining radicals being R hydrocarbon groups linked to tin through carbon and having from one to about eighteen carbon atoms, to form a diorganotinhalide thiocarboxylate 21 in accordance with claim 1, and reacting the diorganotinhalide thiocarboxylate with a mercaptan R SH, wherein R is as above, to form the diorganotin mercaptide thiocarboxylate.

7. A process for preparing a diorganotin alcoholate thiocarboxylate having the formula wherein n is a number within the range from one to about four, R is an organic radical having from one to about thirty carbon atoms, and R is an organic group derived from an alcohol R (OH) wherein n is a number within the range from one to about four and R is a hydrogen group having from one to about thirty carbon atoms, which comprises reacting an acyl halide having the formula wherein X is halide, R is an organic radical having from one to about thirty carbon atoms, and n is a number within the range from one to four, with a diorganotin sulfide having at least one sulfur atom linked directly to tin, the remaining radicals being R hydrocarbon groups linked to tin through carbon and having from one to about eighteen carbon atoms, to form a diorganotinhalide thiocarboxylate in accordance with claim 1 and reacting the diorganotinhalide thiocarboxylate with an alcohol R (OH) wherein n is a number within the range from one to about four and R is a hydrocarbon group having from one to about thirty carbon atoms to form a diorganotin alcoholate thiocarboxylate.

8. A process for preparing a diorganotin dithiocarboxylate having the formula wherein n is a number within the range from one to about four, and R is an organic radical having from one to about thirty carbon atoms, which comprises reacting an acyl halide having the formula dial.

wherein X is halide, R is an organic radical having from one to about thirty carbon atoms, and n is a number within the range from one to four, to form a diorganotinhalide thiocarboxylate in accordance with claim 1, and reacting the diorganotinhalide thiocarboxylate with a thiol acid R C SH to form a diorganotin dithiocarboxylate.

9. Diorganotin thiocarboxylates having the formula wherein n is a number within the range from one to about four, R is a hydrocarbon group having from one to about eighteen carbon atoms, Z is selected from the group consisting of halide and mercapto acid ester radicals wherein m is the number of COOR groups and is within the range from one to about four, R is an organic group derived from an alcohol selected from the group consisting of monohydric and polyhydric alcohols having from one to about four hydroxyl groups and from one to about twelve carbon atoms, and Z is selected from the group consisting of bivalent alkylene radicals having from one to about five carbon atoms and such radicals having a substituent selected from a free carboxylic acid group, a carboxylic acid salt group and a mercapto group, and R is an organic radical having from one to about thirty carbon atoms.

10. Diorganotin thiocarboxylates in accordance with claim 9 wherein Z is a mercapto acid ester radical 11. A process in accordance with claim 1, wherein the acyl halide is an acyl chloride.

12. Diorganotinhalide thiocarboxylates in accordance with claim 10 wherein Z is chlorine, n is two and R is lauryl.

13. Diorganotin mercapto acid ester thiocarboxylates in accordance with claim 10 wherein Z is isooctyl thioglycolate, n is one and R is lauryl.

14. Diorganotinhalide thiocarboxylates in accordance with claim 10 wherein Z is chlorine, n is two and R is stearyl.

15. Diorganotin mercapto acid ester thiocarboxylates in accordance with claim 10 wherein Z is isooctyl thioglycolate, n is one and R is stearyl.

16. Diorganotinhalide thiocarboxylates in accordance with claim 10 wherein Z is chlorine, n is two and R is phenylene.

17. Diorganotinhalide thiocarboxylates in accordance with claim 10 wherein Z is chlorine, n is two and R is butylene.

18. Diorganotin mercapto acid ester thiocarboxylates in accordance with claim 10 wherein Z is isooctyl 3-mercapto propionate, n is two and R is butylene.

References Cited UNITED STATES PATENTS 3,452,825 11/1970 Hoye et al. .s 260-429] 3,063,963 11/ 1962 Wooten et al. 26045.75 K 3,029,267 4/ 1962 Berenbaum et al. 260429.7

WERTEN F. W. BE-LLAMY, Primary Examiner US. Cl. X.R. 260-45.75 K

UNlTED' STATES PATENT oFFIoE CERTIFICATE OF QQRREQTEQN Patent No. 3 T75 451 Dated November 27, 1973 Inventor fis) Lawrence Breaker It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

TGolulmn 1, line 31, "Dirgaiootin" should loe --Diorganotin--.

.Column 3, line 53, "'ohd1oride" should beefiloriclel I ColumnB, lines 28-29, fln the c ese of oolyrners slioolcl be on orle line, as

the heeding for lines 30 to 35 (see line 21). o

. Column '7 lille 67, "cycloelkyl kyl" should be --cvc1oelkyl2lkyl--,

Column 10, line 17, "issoc tyl" should be --isooctyljigs 60 the formula e R ?n--SCI- ---R shot 11d. be R in-Si) R .Co1umn 12, line 38 "deisred' should be --desired--. I

Column 15, line 22 Table I, under the heading of Ex. II, 'Tthiolatic" should be --thiolacfic--. 1

Column 16, line 2, "eighed" should be weighed; line as, Table 11, .across from-45 minutes, first occurrence, "pale yellow" should be ----light yellow---. Y I

zColumn 17 line 2 "monothiastearate" should be -monothiosteara.te--; line 6 thiog1yco1aate" should be --thioglycolate-- Column 20,- claim 4, line 14, "RHOHm should be --R (OH) --5 J UNITED STATES PATENT OFFICE Page 2 CERTIFICATE OF CORRECTION patent 3,775,461 Dated November 27, 1973 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

. Qline 34h claim a "elbow"? should be --a'bout--.-

Column 21, lineiO, claim '7, the formula claims 12 and 14 "tw0" shol 11d be --one Signed and sealed this 15th day of July 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

